Redeployment on Jetty causes "not able to register event"

If I have a Lucee application deployed on Jetty, it starts up just fine. However if I redeploy that application (by replacing the war, for example), when Jetty reloads, the log says

o.e.jetty.servlet.ServletHolder - Servlet.init lucee.loader.servlet.LuceeServlet@241cf0b5 for LuceeServlet
Lucee was not able to register an event listener with org.eclipse.jetty.webapp.WebAppContext$Context

It works fine on a fresh start.
What would be preventing it from reloading?